When, in May, 1917, the need arose for providing masks for the first contingent of the American Expeditionary Forces, the War Department appealed to the Bureau of Mines to provide 25,000 masks within three weeks. Emboldened by the valor of ignorance, the officials of the bureau jauntily undertook the task, making arrangements for the fabric to be produced by a rubber company at Akron, Ohio, and for the masks to be assembled at a factory in Brooklyn. Instead of producing 25,000 masks in three weeks, however, the best they could do was to produce 20,000 in two months. These were immediately shipped overseas. But the rubberized fabric of which they were made was easily penetrated by chlorpicrin vapor, therefore affording very little protection, and they were returned unused. “The only thing about them which is satisfactory,” General Pershing is said to have remarked, “is the strap around the neck.” But the experience thus gained opened the eyes of the authorities to the gravity of the problem, so that when, in July, 1917, the army itself took up the manufacture of gas-masks, it was with a more complete realization of the magnitude of the task by which it was confronted. One of the first steps taken by the War Department, upon assuming charge of mask production, was to give a colonel’s commission to Mr. Bradley Dewey, an officer of the American Can Company, and to place him in command of the Gas Defense Service, as it was then called, but which, upon the organization of the Chemical Warfare Service, became the Gas Defense Division. Thanks to the energy, resourcefulness, and business ability of Colonel Dewey, backed by the efficiency and enthusiasm of the great organization which he created, the American forces in France were protected against gas by masks which, as proved by actual field tests, _gave twenty times the protection afforded by those worn by the Germans_. [Illustration: MAN AND HORSE COMPLETELY PROTECTED AGAINST POISONOUS GAS. In addition to the mask, the man is wearing an anti-mustard gas suit, gloves, and boots. The horse is provided with boots and a gas mask.] [Illustration: TYPES OF GAS MASKS USED BY AMERICAN AND EUROPEAN ARMIES. U. S. Navy Mask (obsolete). U. S. Navy Mask. U. S. C. E. Respirator. U. S. R. F. H. Respirator. U. S. H. T. Respirator. U. S. H. T. Respirator. U. S. Model 1919 Respirator. British Black Veil Mask. British P. H. Helmet. British Box Respirator. French M. 2 Mask. French Tissot Art. Mask. French A. R. S. Mask. German Late-type Mask. Russian Mask. Italian Mask. British Motor-Corps Mask. U. S. Rear Area Emergency Respirator. U. S. Connell Mask.]